1. Field of the Invention
The present invention relates to an incendiary projectile possessing an incendiary composition arranged locally bounded about the internal casing surface of the projectile wall structure.
2. Discussion of the Prior Art
A projectile of the type under consideration herein is known from the disclosure of U.S. Pat. No. 3,981,243, wherein the head space or nose cone of a casing which encompasses a penetrator core is filled with an incendiary mix or composition. In order to enable the effective attacking of combustible materials which are located behind the outer wall structure of a target, the core is provided with grooves along its surface with grooves extending at an incline or spirally relative to the crosssectional plane of the core, and which are similarly filled with an incendiary composition. In that manner, it is intended to achieve that the incendiary composition will not only be effective during penetration into the casing of the target object, but will also be transported along by the core into the innerspace of the target object, in order to more assuredly lead therein to the ignition of combustible materials, especially such as fuel supplies or tanks. cl SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to so develop a projectile of the type which is under consideration herein, so as to produce in the target objects possessing comparatively weak armoring, especially such as sea-vessels and aircraft, a significantly improved synergistic effect from kinetic and thermal energy.
The foregoing object is achieved in that the projectile pursuant to the inventive concept has the inner casing surface of its wall structure covered with the incendiary composition in fixed adherence therewith, and the explosive in the inner space of the projectile extends into grid-structured innerspaces for the mutual bounding of covered regions. In this connection, the invention is also directed to a particularly advantageous method for the formation of a projectile which is designed in this manner, as well as to an expediently employable arrangement for the implementation of the inventive method.
In accordance with the foregoing, it is possible to obtain an overall highly-effective explosive and incendiary projectile, whose casing will disintegrate into highly-effective fragments of relatively good constructively predeterminable size and configuration, with a fixedly adherent covering of incendiary compositions on the rear side of the fragments. As a result thereof, on the one hand, there is assured that the incendiary composition will also be actually transported into the interior of the target upon the piercing of the target casing through the intermediary of the fragment; in essence it, is able to bring into action thermal energy within the casing of the target in addition to the kinetic energy; while, on the other hand, at the selection of an easily ignitable incendiary composition, the development of the reaction gas along the rear side of the fragment will preclude a reduction in the velocity and thereby in the energy of the fragment, inasmuch as any braking vortex and subpressure effects are inhibited on the rear side of the fragments due to formation of the incendiary gas.
The equipping of the internal jacket or mantle surface of the projectile casing with the incendiary composition is preferably carried out through a centrifugal casting method, inasmuch as this allows for the attainment of a mechanically particularly stable homogeneous bonding with the wall structure of the projectile, and subsequently with the fragments which are produced therefrom, inasmuch as the incendiary composition will not loosen or detach itself therefrom during the penetration of the fragments into the structure of the target. The geometry of the fragment formation is essentially determined by the cutting out or scoring of a grid-like matrix structure during the introduction of the incendiary composition on the inner jacket surface of the projectile casing. Through the grid structure which partitions the incendiary composition covering into individual mutually-bounded areas, there is determined the sequence in the ripping open of the wall material (in effect, the fragment formation), inasmuch as the material will preferably tear along such transitional regions between different mechanical damping conditions (between covered and not covered wall material). Through this effect in the influencing of the fragment structure, the cutting out of a grid structure intermediate the covering regions imparts the advantage that there is an increase in the volume which is to be filled with explosive for a projectile of a given caliber (in contrast with a continuous covering of the inner wall structure), and thereby it is possible to further increase the kinetic energy of the fragments which are accelerated by the explosive.
The cutting out or scoring of the grid structure is expediently effected during the course of the centrifugal introduction of the incendiary composition, subsequent to the application of a suitable auxiliary material aid structure, preferably in the form of wax ribs. However, an applicable wax rib network can only be introduced with difficulty, without being destroyed, into the interior space of the projectile and positioned in place therein, the formation of such a grid or network structure being expediently carried out through the intermediary of an axially-parallel divided, and thereby radially outwardly expandable or closable matrix with a groove profiling on its surface in conformance with the intended structure, and into which there is introduced the aid material (such as the liquified wax). Upon the radial drawing together of the matrix, i.e. reduction in diameter, the thereby formed rib structure remains in adherence with the inner jacket or mantle surface of the projectile casing, and during the subsequent centrifugal casting in of the incendiary composition serves as a nucleus or core for the cutting out or scoring of the grid structure in this covering. In comparison with the known loose inserting or glueing in of externally preformed incendiary composition sections or bodies, there is obtained a geometrically more readily predeterminable configuration of the incendiary composition covering, with an intimate bonding to the material of the future fragments, in contrast as would the case of a moisture or vapor-free adhesive bonding obtainable in the prior art.
When, in connection with the present invention, reference is made in general with regard to an incendiary composition, this does not represent any restriction to an incendiary composition in the narrower sense as being constituted from an oxidizer and a reducing medium. Preferably, this cast-in and, in essence, especially good adhering, structured internal covering with a defined cut out or scored grid structure is, namely, constituted of a so-called active incendiary material, which essentially consist of only the reducing medium, which reacts with the hot fuel gas clouds upon the detonation of the explosive, and thereafter maintains the incendiary reaction, inasmuch as the surrounding air serves as the oxidizer. Adapted as such easily ignitable active incendiary compositions which burn down at a-high degree of temperature, are especially those zirconium or titanium alloys which are sold by Quantic Industries, Inc., San Carlos, California, USA, under the commercial designations QAZ/QAT; whereby the utilization of titanium as the basic material, besides the good incendiary effect also presents the economic advantage that, from the employment of welding electrode remainders, it is available relatively inexpensively and in large quantities, and can be easily worked in a centrifugal casting process. However, any other pyrophoric; in essence, incendiary-active materials can be centrifugally cast into the projectile, within the scope of the present invention, as an incendiary composition 20 covering with a pregiven grid structure especially such as the so-called cermix metals, or misch metals, a mixture of rare-earth metals which readily react with oxygen, inasmuch as because of its easy ignitability and high combustion heat it is available as a basic material for pocket lighter flints.